In the food industry, stirring installations are amongst others used during the production of beverages. Beverages are in most cases composed of a plurality of ingredients, that is at least a concentrate and water, for example fruit syrup and water. A production step, which is particularly important in the end phase of production, is to make sure that the end product is homogenous. This step is also important in case an already produced end product that has been stored for a while has to be shipped to consumers. During the storage, the mixed liquid may change its homogeneity due to different viscosities and densities of the ingredients. If the liquid is simply bottled without any treatment, the result may be that each dose has a different taste, consistency, etc. Thus, the liquid has to be made homogenous again. This is accomplished by using stirring installations to remix the liquid. Normally, the liquids are stored in large containers of 500 or 1000 liters. These containers are typically made of plastic by forming them in one piece.
For stirring or mixing a liquid, solutions proposing the usage of a support rod rotated by a motor and having mounted to it at least one pair of blades of the type of a propeller have been provided. A disadvantage of these solutions is the fact that, when the product level in the container is as low as substantially the rotation plane of the blades, the blades “flap” during their rotation and introduce air into the product, which is undesired and which again may lead to an inhomogeneous product.